example.js

function getPeople(callback) {
  $.get("people", callback);
}

function getPerson(id, callback) {
  $.get("person/{id}", callback);
}

function storePerson(data, callback) {
  db.call("INSERT INTO PEOPLE VALUES {data}", callback);
}

getPeople(function(people) {
  for(person in people) {
    getPerson(person["id"], function (personData) {
      storePerson(personData, function (dbOK) {
        console.log("person stored");
      }
    }
  }
})
      
      
function getPeople() {
  return fetch("people");
}
      
function getPerson(id) {
  return fetch("person/{id}");
}
      
function storePerson(data) {
  return db.call("INSERT INTO PEOPLE VALUES {data}");
}
      
getPeople().then(people => {
  for (person in people) {
    getPerson(person["id"]).then(data => {
      storePerson(data).then(dbOK => {
        console.log("person stored");
      });
    })
  }
})
      
let people = await getPeople();
for (person in people) {
  let data = await getPerson(person["id"]);
  let dbOK = await storePerson(data);
  console.log("person stored");
}